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RE: normally open irrigation valve

I need to set up 2 valves that would be constantly open and close when activated by the controller. Do I need a special valve? How can I make this work?

If you can't find a valve to do what you want, it's possible to build something that will logically work the way you want it to.

Conceptually, all you need is an AC adapter (like from an old irrigation controller) and a pair of relays with 'Normally Closed' contact points (you also need to know a little about electricity so you can make sure you get components that will work within the limits of your irrigation controller and valves).

You basically have the irrigation controller power the relays. When the controller is 'OFF', the relay contacts are closed, and the AC adapter can powers the valve turning it on. When the controller is 'ON', it opens the relay contacts and the valve loses power and closes.

Keep in mind that if you should follow this idea, irrigation valves are usually not designed with the idea that they are going to be usually 'ON' most the time. You also need to know a little bit about electricity so you can make sure you get parts that will work within the limits of the irrigation controller and irrigation valves. (As an example, if you get relays that draw too much power when activated by the controller, you could burn out the controller. If you get an AC adapter that is too high in voltage, you can burn out the solenoid in the valve.)